The invention relates to rotary machines that have a fluid chamber of changing volume, as in an engine or a pump.
Rotary machines of this type employ a rotating surface to have a working relationship with a fluid, e.g. compression or expansion. In the case of an engine, the machine also generates shaft energy as where a compressed gas and fuel mixture is ignited for explosive expansion within the chamber of the machine.
Prior rotary machines have typically employed one eccentric rotor or multiple adjacent rotors that turn in opposite directions so that adjacent rotor surfaces move in the same direction; however, machines having rotors turning in the same direction have been suggested.